In recent years, the need for integrated circuits operating in the microwave or millimeter wave band has increased due to the widespread use of mobile communications devices such as cellular phones. As consumers demand more functionality from their mobile communications devices, the need for more complex integrated circuits increases. As a result, highly integrated circuits with radio frequency based components have been developed having passive components, such as resistors, capacitors, inductors, and baluns.
Passive components may have their characteristics significantly altered when located directly on an integrated circuit that is operating in a radio frequency band. Consequently, passive components are positioned on a separate integrated circuit or on a separate package so as to prevent interaction between the active components and the passive components. Properly positioning the passive components also involves distancing them from active components, thus increasing the size of the device being manufactured.
In addition, passive components must be positioned away from wires connecting active components. For example, an active component mounted in a package or on a substrate has bonding wires used for electrical connection purposes. The bonding wires tend to have substantial electrical influence on any nearby passive components. In order to obtain the expected circuit performance of passive components, it is important to minimize the effect of such electrical influence.
One method for reducing the above-mentioned electrical influence is to increase, as much as possible, the number of bonding wires that extend from within the active component and connect to either lead frames or slugs, located immediately below the active component. In doing so, a number of bonding wires are arranged in parallel connection, thus reducing the total electrical influence of the bonding wires.
However, this method for minimizing electrical influence has problems. As the number of bonding wires increases, the size of the device being manufactured quickly becomes larger due to the space required between bonding wires. If bonding wires are too close, electromagnetic coupling can occur, thereby reducing component performance. Thus, a conflict occurs between keeping the component size small and the need to reduce electrical influence.
As remarkable technological progress has been achieved in the field of telecommunications in recent years, the frequency band used in communication devices has upwardly shifted from the microwave band to the millimeter-wave band. Detrimental effects, such as parasitic capacitance exerted by active components on passive components, become larger in proportion to the level of the frequency used in the communication devices. This creates additional problems with the integration of active and passive components.
As it becomes possible to fit more and more components onto a single substrate, a correspondingly larger number of interconnects may need to be fabricated on the substrate to connect the components. Conventional interconnects are typically formed on the same side of the substrate as the components and terminate at contact pads around the perimeter of the substrate. With each increase in the number of components on a single substrate, the interconnects and contact pads around the perimeter of the substrate typically become more crowded. However, in order to prevent detrimental effects, passive components cannot be crowded with active components or their interconnects.
What is needed therefore is a way to compactly integrate passive components with active components and their interconnects while preventing detrimental interaction between the passive and active components.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.